It seems that as long as there continue to be boxers, there will continue to be movies based on their true stories. That so many of these stories are similar to one another hardly matters. He’s poor; he’s a nobody; he just needs a chance; someone is holding him back — it’s a formula. And we like it.

Micky Ward is the subject of “The Fighter,” and his story is as nondescript as the title. But in the capable hands of director David O. Russell (“Three Kings,” “I Heart Huckabees”), working from a screenplay by Scott Silver, Paul Tamasy, and Eric Johnson, Micky Ward’s hardscrabble rise to the top — OK, to the middle — makes for a compelling underdog sports drama.

Played with his usual earnestness by Mark Wahlberg, Micky is an amateur boxer in the mid-’90s in Lowell, Mass., an economically depressed dump 30 miles from Boston. His older half-brother, Dicky Eklund (Christian Bale), used to be a fighter too — his claim to fame is a 1978 match with Sugar Ray Leonard — but now he’s is a full-time crack addict. Dicky, self-described as being “squirrelly as f***,” hopes for a comeback, though the crack addiction makes this unlikely. In the meantime, he’s acting as Micky’s trainer, with their mother, Alice (Melissa Leo), serving as manager.

After a disastrous fight against an opponent who outweighs him, Micky hears of opportunities to train in real facilities, for real money. Alice’s reaction: “You can’t trust him, he ain’t family.” Also untrustworthy, in Alice’s view, is Micky’s new girlfriend, a sweet but trash-talking bartender named Charlene (Amy Adams). Alice believes no one who isn’t a blood relative should be allowed to influence Micky’s actions. It doesn’t matter that Alice is a poor manager and Dicky is too cracked-out to be a good trainer. They are right for their jobs by virtue of being Micky’s mother and brother.

Lowell is depicted as a town full of loud, sweaty white trash where everybody drinks and fights a lot. Alice bore Dicky and Micky plus seven — seven! — other children, all girls, each skankier than the last. (They hate Charlene because she is slightly less skanky than they are.) It’s hard not to mock characters like that, but “The Fighter” generally treats them seriously. Russell doesn’t downplay their lower-class foibles; he just uses naturalistic touches rather than big, broad strokes to depict them. It’s a tramp stamp here, a pair of gaudy earrings there, a ratty hairstyle on this one, a crack-smoker’s smile on that one.

Melissa Leo, who earned an Oscar nomination for “Frozen River” a few years ago, shines again here as Micky’s jealous, flawed mother. Familiar TV actor Jack McGee (“Rescue Me”) helps out as her second husband. For added authenticity, Micky’s trainer and mentor, a cop named Mickey O’Keefe, is played by the actual Mickey O’Keefe who trained Micky Ward.

It’s hard not to see shades of “Rocky” and “Raging Bull” in some of the story details, but by no means does “The Fighter” come off as a retread. By focusing on the volatile relationship between brothers Micky and Dicky, Russell finds a wealth of emotional material, not to mention human comedy. (“The Fighter” is much funnier than you might expect it to be.) Wahlberg, rock-solid in the lead, may be overshadowed by Bale, whose fully formed drug-addict character is astonishingly real. Yet in the end, I was surprised at how invested I was in Micky’s boxing career, not in Dicky’s personal demons. The film’s final match is terrifically exciting, in part because of the thrilling way Russell shoots it, but mostly because of how eager we are for Micky to succeed.